This invention relates to a push-pull arrangement, including a push block assembly, of the types illustrated in U.S. Pat. Nos. 3,434,738 and 3,469,861, both assigned to the assignee of this application. Such arrangements each comprise a bail pivotally mounted on the forward end of one vehicle to selectively engage a hook mounted on the rearward end of another vehicle for towing purposes. In addition, a push block is mounted on the forward end of the former vehicle for push loading purposes. This arrangement is particularly useful to increase the versatility and the efficiency of tractor-scrapers (particularly tandem-powered) over a wide range of work tasks.